I deal with Dell on a business account and I know they have quarterly sales targets – so if you’re buying around the end of a quarter (next one is end Jan I think) and speak direct to a sales rep he is much more likely to be flexible on price in order to meet their targets.
I’ve been amazed at the discounts they are willing to give – eg I was buying a rack server last summer, spec’ing it up with the guy on the phone and he asks if there is anything else I want with it – I tell him a KVM over IP switch would be nice if not for the price (knowing they retail at £3K). He asks how much budget I have left and I say £500. He lets me have it. ( I should have told him £250 🙄 ).
Btw the 24″ is listed at £479 ex Vat on my Dell premier page.